Georg Christian Unger based his plans on a drawing by the Italian archeologist Francesco Bianchini from his 1738 volume Del Palazzo de’ Cesari. Biancini had tried to reconstruct the Imperial Palace on the Palatine Hill in ancient Rome. The only sources he used were ancient writers, parts of the ruins, and an inscription of a building with fountains on a coin he found in the Nero-erected market marcelum magnum in Rome. The ancient gold piece shows an enclosed room, an open rotunda with a vaulted ceiling, and attached on both sides to open walkways.